Table 1.
Characteristics of Participants Across Sleep Duration
| ≤6h (n=831) |
7h (n=1575) |
8h(Mean) (n=3893) |
≥9h (n=1871) |
P Valuea | Total (n=8170) |
|
|---|---|---|---|---|---|---|
| Age (years) | 57.1±13.9 | 51.4±13.7 | 47.8±14.1 | 50.4±17.0 | <0.0001 | 50.0±14.9 |
| Male (n, %) | 459(55.2%) | 842(53.5%) | 2082(53.5%) | 986(52.7%) | 0.6852 | 4369(53.5%) |
| BMI (kg/m2) | 23.5±3.5 | 23.6±3.5 | 23.4±3.4 | 23.1±3.4 | 0.0002 | 23.4±3.4 |
| Rural region (n, %) | 461(55.5%) | 958(60.8%) | 2699(69.3%) | 1327(70.9%) | <0.0001 | 5445(66.6%) |
| Educational attainment | <0.0001 | |||||
| Low (n, %) | 655(78.7%) | 1118(71.0%) | 2871(73.7%) | 1551(82.9%) | 6195(75.8%) | |
| Medium (n, %) | 143(17.2%) | 348(22.1%) | 795(20.4%) | 266(14.2%) | 1522(19.0%) | |
| High (n, %) | 33(4.1%) | 109(6.9%) | 227(5.9%) | 54(2.9%) | 423(5.2%) | |
| Household income per capita | <0.0001 | |||||
| Low (n, %) | 55(6.71%) | 117(7.5%) | 359(9.3%) | 211(11.4%) | 742(9.2%) | |
| Medium (n, %) | 275(33.5%) | 491(31.5%) | 1354(35.1%) | 714(38.7%) | 2834(25.1%) | |
| High (n, %) | 490(59.8%) | 951(61.0%) | 2147(55.6%) | 919(49.8%) | 4507(55.7%) | |
| Geographical region | <0.0001 | |||||
| Northern region (n, %) | 406(48.9%) | 702(44.6%) | 1692(43.5%) | 687(36.7%) | 3847(42.7%) | |
| Southern region (n, %) | 425(51.4%) | 873(55.4%) | 2201(56.5%) | 1184(63.3%) | 4683(57.3%) | |
| Total energy intake (kcal/d) | 2030.6±717.3 | 2134.8±652.1 | 2162.7±641.5 | 2122.8±686.8 | <0.0001 | 2134.8±665.9 |
| Current smoker (n, %) | 255(30.7%) | 421(26.7%) | 1054(27.1%) | 506(27.0%) | 0.1583 | 2236(27.4%) |
| Alcohol drinking (n, %) | 285(34.3%) | 543(34.5%) | 1280(32.9%) | 577(30.8%) | 0.1066 | 2685(32.9%) |
| Physical activity | <0.0001 | |||||
| Low (n, %) | 528(62.5%) | 901(57.2%) | 1944(49.9%) | 963(51.5%) | 4336(53.1%) | |
| Moderate (%) | 103(12.4%) | 244(15.5%) | 594(15.3%) | 238(12.7%) | 1179(14.4%) | |
| High (n, %) | 200(24.0%) | 430(27.3%) | 1455(34.8%) | 670(35.8%) | 2655(36.5%) | |
| Medical history | ||||||
| Diabetes (n, %) | 35(4.2%) | 46(2.9%) | 92(2.4%) | 60(3.2%) | 0.0205 | 233(2.9%) |
| Hypertension (%) | 170(20.5%) | 210(13.3%) | 405(10.4%) | 271(14.5%) | <0.0001 | 1056(12.9%) |
| MI (n, %) | 13(1.6%) | 20(1.3%) | 23(0.6%) | 22(1.2%) | 0.0100 | 78(1.0%) |
| Stroke (n, %) | 17(2.0%) | 11(0.7%) | 39(1.0%) | 39(2.1%) | 0.0002 | 106(1.3%) |
| Blood pressure | ||||||
| SBP (mmHg) | 130.5±20.8 | 125.7±18.9 | 123.0±17.8 | 124.0±20.0 | <0.0001 | 124.7±19.0 |
| DBP (mmHg) | 82.7±11.5 | 81.0±11.4 | 80.2±11.0 | 79.6±11.5 | <0.0001 | 80.5±11.3 |
| Hs-CRP (mg/L) | 1.80±1.88 | 1.70±1.88 | 1.55±1.74 | 1.73±1.90 | <0.0001 | 1.64±1.82 |
| TG (mmol/L) | 1.78±1.46 | 1.67±1.52 | 1.68±1.52 | 1.66±1.46 | 0.0278 | 1.68±1.50 |
| LDL-C (mmol/L) | 3.11±0.97 | 3.03±0.97 | 2.95±0.99 | 2.92±0.95 | <0.0001 | 2.97±0.98 |
| HDL-C (mmol/L) | 1.45±0.39 | 1.44±0.49 | 1.44±0.55 | 1.43±0.43 | 0.2854 | 1.44±0.50 |
| UA (μmol/L) | 316.5±98.5 | 306.8±110.9 | 306.8±105.0 | 307.9±110.1 | 0.0408 | 308.1±106.7 |
| Glucose (mmol/L) | 5.51±1.50 | 5.37±1.34 | 5.30±1.38 | 5.33±1.47 | <0.0001 | 5.34±1.41 |
| Insulin (uIU/mL) | 14.91±28.31 | 13.78±19.04 | 14.17±21.58 | 14.89±26.44 | 0.1055 | 14.33±23.10 |
Notes: Data are expressed as the mean ± SD or as number (percentage). aP value represents the significance of difference across sleep duration categories. P values were determined by one-way analysis of variance or Kruskal–Wallis test for continuous variables and Pearson χ2 statistic for categorical variables.
Abbreviations: BMI, body mass index; MI, Myocardial infarction; SBP, systolic blood pressure; DBP, diastolic blood pressure; hs-CRP, high sensitive C-reactive protein; TG, triglycerides; LDL-C, low density lipoprotein cholesterol; HDL-C, high density lipoprotein cholesterol; UA, uric acid. Glucose: Fasting serum glucose. Insulin: Fasting serum insulin.